Archivos de diario de noviembre 2022

19 de noviembre de 2022

Rediscovering an Overlooked Lichen Moth in Colombia and Venezuela

Resumen (español): El género Eudesmia incluye alrededor de 14 a 18 especies similares y se distribuye desde el suroeste de los Estados Unidos hasta el sur de América del Sur. Eudesmia lunaris es una especie distintiva que se encuentra en Colombia y Venezuela. Único dentro del género, es reconocible por las estrechas rayas anaranjadas cerca de la base de las alas anteriores, en combinación con los estrechos bordes anaranjados de la base de las alas anteriores y una mancha oscura en el tórax. Encontré alrededor de 38 observaciones de esta especie previamente no reconocida en iNaturalista.

Lichen moths of the genus Eudesmia Hübner are easily recognizable with their black wings that are boldly banded with orange or yellow.

Eudesmia arida, Texas @gcwarbler | E. nr menea, Panama @josuergg | E. australis, Brazil @pajeu

About 14 to 18 species are known from the genus at present. The genus is distributed from the southwestern United States to southern South America. Although they are easily recognized as a group, several species are difficult to separate in the field. This is the result of several factors: (1) many species are, indeed, quite similar; (2) original descriptions are often very brief and scattered in early literature; (3) a lot of individual variation in patterns was not appreciated by early researchers, resulting in the unnecessary naming of "new" species; (4) there is no recent revision of the genus nor any handy modern field guide to aid identification of the moths in this genus.

I have been digging back into the literature and trying to sort out some of the Eudesmia species which seem to have been overlooked in modern times. For instance, among the 17 species listed in iNaturalist's taxonomy as of 1 November 2022, images of only seven species had been uploaded. As well, since many observers just choose the most numerous or most-identified species as a suggested identification, the proportion of misidentified images is high.

As I read back through the original literature, one species described from Colombia seemed to stand out in that it ought to be quite recognizable. "Cisthene" [= Eudesmia] lunaris was described by Francis Walker in 1865 from a male specimen in the British Museum. Among other details, he mentions that the species has "a pale luteous [yellow-orange] subcostal streak extending from the base [of the forewing]" and "a pale luteous streak extending along the interior border from the base to the first [orange] band." Those orange streaks in the basal area and on the inner margin of the forewings are not evident in any other species in the genus. Hampson (1900) and Draudt (1918) published rather smudgy illustrations of lunaris which may have done more to obfuscated its identity rather than to help identify the species.

So I began perusing observations of Eudesmia uploaded from Colombia and Venezuela and immediately found dozens of images which match Walker's description.


E. lunaris, Colombia @smejiadu | E. lunaris, Colombia @juan-sebastian-leon-lleras | E. lunaris, Venezuela @fherrerav

They were also easy to separate from other Eudesmia because, unlike most other Eudesmia moths in that region which have a solid orange thorax, the newly separated Eudesmia lunaris more often than not have a small to large black spot in the center of the thorax and often small black dots at the front end of the tegulae (small tracts of scales flanking the thorax).

As of this evening (11/18/2022), I have put the name Eudesmia lunaris on about 38 iNat observations. The species appears to range from southwestern Colombia northeast to northern Venezuela near Caracas. Observations have been made in the lowlands, intermontane valleys, and lower Andean foothills up to 1,500 m elevations (mostly below 500 m). @gregory_nielsen uploaded the earliest image of Eudesmia lunaris on iNat, near Villavicencio, Colombia, and remarkably also documented the larva and pupa, almost certainly the first ever images of those.


Eudesmia lunaris larva, pupa, and adult; near Villavicencio, Meta Dept., Colombia @gregory_nielsen

One remaining conundrum was the identity of "Cisthene curvifera", described by Walker in 1865 on the same page as his Cisthene [= Eudesmia] lunaris. I noticed that the description of curvifera was very similar to that of lunaris, and that it had been described from a single female specimen from the same location (Bogota) and same collection ("Mr. Stevens") as lunaris. Curvifera seems not to have been illustrated anywhere and is not mentioned by any subsequent authors except in a list by Butler (1877). It seems pretty apparent that curvifera simply represents the female of Walker's lunaris; no one else seems to have bothered to point this out. I have a manuscript in preparation on the genus Eudesmia which will formally suggest that synonymy.

My thanks to the many iNaturalists who have uploaded their images of this and related species, and to @pfau_tarleton for coaching me on some of the formatting in this post!

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24 de noviembre de 2022

Pattern Variation in Eudesmia Lichen Moths

Resumen (español): Describo e ilustro la variación en el tono y el patrón de color que se encuentra en los miembros del género de polillas del liquen Eudesmia.

I recently posted a journal entry describing my "rediscovery" of a species of Eudesmia lichen moth, Eudesmia lunaris, which had been overlooked for over a century. As I mention there, part of the difficulty in identifying moths in this genus deals with their pattern and color variability. I'm still going through thousands of images to sort out additional species which may have been overlooked, but I wanted to take a moment to demonstrate how much variability there can be.

The array below shows examples of Eudesmia arida, the northernmost member of the genus and the only species occurring with any regularity in the United States (Arizona to West Texas). Since no other species in the genus has been documented in this U.S. range, I make the assumption that all the examples uploaded to iNaturalist in the region are, in fact, Eudesmia arida. (I can't make such an assumption further south in the Neotropics.)

Eudesmia arida comparison
Eudesmia arida (all), Upper row: Texas @gcwarbler | Arizona © @finatic | Arizona @psyllidhipster | Arizona @silversea_starsong
Lower row: Arizona @matt_lachiusa | Arizona @court_rae | Arizona © @jaykeller | Arizona @fowlivia

It is apparent when looking at the array of Eudesmia images for just about any species that there is variation in the following aspects:
-- Color hue: Most species show some variation in the color bands and patches from rich golden orange to pale orange, in some cases to deep yellow, pale yellow, or even creamy white color. In Eudesmia arida, most moths have relatively rich orange color patches (above, upper row), but occasional yellow forms are found (lower row). A few species in the genus, especially those in southern South America, tend to be dominated by paler color bands. The amount of color hue variation differs among species and may have regional, seasonal, and sexual components to the variation, but this has not been investigated in any detail.
-- Band widths: One of the most striking aspects is the variation in the width of the orange color bands and smaller details of their shape; note the variation from L to R in each row, above. Certain gross generalizations tend to hold true for each species but the wide variation in these aspects lead several early researchers to name new species based on perceived band-width differences from examination of very few specimens. We benefit now from the wealth of additional images of living examples in repositories such as iNaturalist. Unfortunately, some of the species described in early literature were distinguished also by details of hindwing color pattern (e.g. the width of the marginal black band on the hindwings) and the color of the abdomen, neither of which can be seen in most images of living moths in natural posture. Every image on iNaturalist which shows any hint of the hindwing or abdominal coloration is so valuable for this reason!
-- Size differences: Males of most Eudesmia species are anywhere from 10 to 30% smaller than females (see below). Combined with the variation mentioned above, this probably lead Walker to name the male and female of E. lunaris as different species. The image of a mated pair of Eudesmia ruficollis below, taken by Maria Izabel L. Mosini (@bebelmosini) in São Paulo, Brazil, demonstrates both the size disparity and color differences which can be observed in many species. The differences are not always this dramatic, but it's something to keep in mind.

https://www.inaturalist.org/observations/133957920

Eudesmia ruficollis, mated pair, 18 April 2020, São Paulo, Brazil @bebelmosini

A few future journal posts will deal with the recognition of other distinctive species of Eudesmia found in Mexico and southern South America which can apparently be distinguished by certain details of head/thorax/abdomen coloration. Stay tuned!

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27 de noviembre de 2022

Uncovering another lichen moth: Eudesmia aymara from Bolivia

Resumen (español): Después de estudiar la literatura sobre varios géneros de polillas de líquenes, descubrí una observación de Eudesmia aymara, una especie local y aparentemente poco común del centro de Bolivia. La observación fue realizada por @eldirko en enero de 2021. [En la taxonomía de iNat, esta especie solía ser incluida en el género Vianania. Posteriormente Bendib & Monet (1999) colocaron Vianania como sinónimo de Eudesmia.]

This is kind of fun! I’ve spent many days recently delving into the literature on the lichen moths of the genus Eudesmia and related genera such as Vianania, etc. This can be pretty tedious, but I really enjoy little discoveries along the way. Well, today I made a big “discovery” in this group of moths.

Eudesmia aymara was described originally in the genus Vianania by Ricardo N. Orfila in 1953 from a few specimens collected in Bolivia. The original description (of both the new genus and species) is in the Spanish-language journal, Physis, the official bulletin of the Argentine Association of Natural Sciences (Asociación Argentina de Ciencias Naturales). Hernan M. Beccacece of the National University of Córdoba (Argentina) was kind enough to send me a pdf of the original paper by Orfila. Almost simultaneously in my literature review, I came across a listing of “Type material of Arctiinae…in the Museo Argentino de Ciencias Naturales” (Rodriguez-Ramirez et al. 2020. Zootaxa 4742) which included photographs of the holotype specimen of Vianania aymara. [Incidentally, although Orfila does not explain the name, “aymara” refers to a population of indigenous people of Bolivia and their language.] As I read through Orfila’s description and looked at the photos in the other paper, I once again came to the conclusion that it ought to be recognizable in field photos. However, as of earlier today (11/26/2022), there were no observations of any Vianania or Eudesmia moths on iNaturalist from Bolivia, despite there being at least two and maybe three species occurring in the country.

So I began a search through tiger and lichen moths (Arctiinae) from Bolivia, which numbered some 1,500 observations. Several pages into this set of observations, I suddenly came across this observation by Dirk Dekker (@eldirko), made in the Sucre municipality, Chiquisaca Dept., Bolivia, in January 2021:
https://www.inaturalist.org/observations/68895776
Eudesmia aymara, Bolivia, Dirk Dekker (iNat)
It is a perfect match to Orfila’s description and the illustration of the holotype specimen (which I can’t link to because of copyright restrictions). I finished going through the rest of the Arctiids in Bolivia and found no other examples. So Dirk’s image is the first photo of a living example of the species, and to date, the only one.

The species is recognized by the combination of marks I mention in Dirk’s observation, above, namely:
-- orange collar
-- black thorax and abdomen
-- pale yellow median band on the forewings consisting of 4 separate spots (innermost reduced to a dot)
-- two yellow subterminal patches on forewings
-- hindwing broadly yellow at base, with black terminal band
From Orfila’s specimens and Dirk Dekker’s image, the species has only been documented in two locations in mountainous central Bolivia. It makes me wonder what other unrecognized discoveries are hidden among unidentified observations on iNaturalist!


DRAFT map of the distribution of five species of Eudesmia in southern South America. Data are from iNaturalist observations as of 8 December 2022 plus a few earlier records from the literature.

Acknowledgements: Thanks to Dirk Dekker (@eldirko) for uploading this important observation! I also thank Hernan M. Beccacece (Universidad Nacional de Córdoba, @hernan24) and Juan López-Gappa (Museo Argentino de Ciencias Naturales Bernardino Rivadavia) for providing difficult-to-locate references. Jose Balderrama (@jose_balderrama) helped with Bolivian placenames. Lucas Rubio (@lrubio7) helped update the taxonomy on iNaturalist.org. Tony Iwane (@tiwane) helped me trouble-shoot the syntax for this post.

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Recognizing Eudesmia australis (Orfila, 1935)

Eudesmia australis (Orfila, 1935)

Cisthene australis Orfila, 1935. Rev. Soc. Entomol. Arg. 7:225-226.
Vianania australis Orfila, 1953. Physis 20(59):483-484.
[Bendib & Minet (1999) synonymized Vianania under Eudesmia.]

Resumen (español): Eudesmia australis se puede reconocer por las pequeñas manchas anaranjadas en el collar y las manchas anaranjadas subapicales "triangulares" en las alas anteriores. La especie se encuentra desde el estado de Santa Catarina, Brasil, hasta el sur del departamento de Buenos Aires, Argentina.


Eudesmia australis: Argentina @claudianr | Argentina @luchoperalta | Uruguay @gmmv80

Like other southern South American members of the genus, Eudesmia australis has (1) two orange subterminal patches instead of one orange crescent, and (2) a median orange or yellow band which often has irregular margins, bulges in the middle, and narrows at the costa and inner forewing margins. Of the two subterminal patches, the shape of the subapical one has been described as "subtriangular" or "triangular" (Orfila 1935, 1953), refering to the fact that the patch is widest in the middle, its basal edge forms a broad obtuse angle, and the distal margin is evenly and gently curved. This is similar to the same patch on E. ruficollis of Brazil and contrasts with the rectangular or crescentic subapical patch on E. argentinensis. The thorax is mostly black with two widely separated spots of orange on the collar, unlike the nearly continuous orange collar of both E. argentinensis and E. ruficollis. There appears to be a general trend for the orange on the collar to be slightly more extensive towards the northern part of the range of this species, thus approaching the continuous orange collar shown on E. ruficollis.

On iNaturalist, Eudesmia australis has been documented from southern Brazil, through Uruguay, and into southern Buenos Aires province, Argentina, where the species apparently overlaps with Eudesmia argentinensis. The westernmost images on iNaturalist are near Tornquist, Buenos Aires Province. The northernmost images are from the state of Santa Catarina, Brazil.


DRAFT map of the distribution of five species of Eudesmia in southern South America. Data are from iNaturalist observations as of 8 December 2022 plus a few earlier records from the literature.

Orfila, R. N. 1935. Lepidoptera Neotropica, II. Dos nuevas especies de Noctuoidea. Rev. Soc. Entomol. Arg. 7:225-226.

Orfila, R. N. 1953. Notas sobre Lithosiidae, I. El género Eudesmia Hb. y un género y especie nuevos. Physis 20:474-485.

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28 de noviembre de 2022

Moth Photographers Group tips

Jack mentioned Moth Photographers' Group in a previous post. I recently wrote a journal entry which outlines some tips for using MPG. I'm cross-posting a link to that offering here:
https://www.inaturalist.org/posts/65486-a-couple-of-tricks-for-moth-identification-using-mpg

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